1. Field of the Invention
Embodiments of the invention generally relate to a method and apparatus for monitoring catalyst requirements of a fluid catalytic cracking catalyst injection system, and the like.
2. Description of the Related Art
FIG. 1 is a simplified schematic of a conventional fluid catalytic cracking system 130. The fluid catalytic cracking system 130 generally includes a fluid catalytic cracking (FCC) unit 110 coupled to a catalyst injection system 100, an oil feed stock source 104, an exhaust system 114 and a distillation system 116. One or more catalysts from the catalyst injection system 100 and oil from the oil feed stock source 104 are delivered to the FCC unit 110. The oil and catalysts are combined to produce an oil vapor that is collected and separated into various petrochemical products in the distillation system 116. The exhaust system 114 is coupled to the FCC unit 110 and is adapted to control and/or monitor the exhausted byproducts of the fluid cracking process.
The catalyst injection system 100 includes a main catalyst source 102 and one or more additive sources 106. The main catalyst source 102 and the additive source 106 are coupled to the FCC unit 110 by a process line 122. A fluid source, such as a blower or air compressor 108, is coupled to the process line 122 and provides pressurized fluid, such as air, that is utilized to carry the various powdered catalysts from the sources 102, 106 through the process line 122 and into the FCC unit 110.
A controller 120 is utilized to control the amounts of catalysts and additives utilized in the FCC unit 110. Typically, different additives are provided to the FCC unit 110 to control the ratio of product types recovered in the distillation system 116 (i.e., for example, more LPG than gasoline) and to control the composition of emissions passing through the exhaust system 114, among other process control attributes. As the controller 120 is generally positioned proximate the catalyst sources 106, 102 and the FCC unit 110, the controller 120 is typically housed in an explosion-proof enclosure to prevent spark ignition of gases which may potentially exist on the exterior of the enclosure in a petroleum processing environment.
Due to the danger of spark ignition near the FCC system, the enclosures utilized to house the controller are configured to meet applicable government regulations, industrial standards and/or processor standards. For example, in the United States, the controller must be housed in Class I, Division 1 explosion-proof enclosure as described in Section 500 of the National Electric Code (NEC).
Explosion-proof enclosures meeting such safety standards typically include a cast metallic body having a lid bolted thereto utilizing a plurality of fasteners. Thus, access to the contents of the enclosure, e.g., a controller, requires a time-consuming process of removing a plurality of bolts. Moreover, as the controller is now exposed to the potentially hazardous environment, high-level authorization from plant operations management is typically required as certain processing activities must be stopped to minimize the presence of hazardous gases. In addition, special safety precautions are frequently required when opening the enclosure, such as monitoring the air in the region surrounding the enclosure for flammable gas content, provision of extra fire extinguishing equipment, covering or closing off of gratings over drainage channels, among other safety measures. Thus, servicing or obtaining items within the housing, such as a disk containing historical information regarding catalyst injection events from the controller, is both difficult and time consuming, and may require an interruption in processing activities.
Moreover, as catalyst usage information is retrieved only periodically from the injection system, the amount of catalyst inventoried (i.e., catalyst warehoused and queued in the injection system) at a facility is often difficult to determine. Particularly as catalyst injection may be unscheduled (i.e., not part of production planning) due to instantaneous needs or to correct process trends, the rate of catalyst usage may vary while the amount of catalyst stored in the injection system may not be known until downloading that information from the injection system's controller. Thus, it is often difficult to predict when additional supplies of catalyst needs to be delivered to a production facility. Furthermore, as many production facilities are located in remote regions of the world, lead times needed to deliver catalyst are often long, creating costly need to airfreight catalyst to avoid adverse production results and/or quality or even shutdown of refinery operations.
In addition, re-ordering of catalyst inventory is normally initiated by high level employees such as refinery operations management personnel. This is due to the high dollar value of the catalyst being ordered, which prevents this task being delegated to lower level employees. These operations management personnel are generally employed to carry out a variety of other tasks, many of which are of an immediate and urgent nature each day. Because re-ordering of catalyst is a function that does take place on a frequent basis, this is a task that tends to be forgotten until it is too late, causing extra cost to the refiner and/or the supplier through having to air-freight or express ship catalyst to the refinery in an emergency mode, rather than using more efficient and less costly surface transportation means.
At present, one way that operations managers deal with this situation is by over-ordering catalyst. This is a very inefficient method of dealing with the problem as it leads to refiners having to carry excessively high inventories of expensive catalytic materials, tying up large amounts of capital. This method also frequently only postpones the “panic re-ordering” problem referred to above, rather than preventing it, as re-ordering now becomes even less frequent, and is even more easily forgotten. Thus a means of automating the re-ordering process will be of great benefit to refiners and to catalyst suppliers.
Therefore, there is a need for an improved method and apparatus for monitoring catalyst requirements of a fluid catalytic cracking catalyst injection system.